File Scan Service

I have a Samsung Galaxy S3 with this app installed but every time i open it and try and do a backup it says “file scan running” and this takes a long long time and doesnt allow me to do anything. I’ve tried leaving it to index the content etc overnight but i still keep getting the same messages. I never used to have this problem until I updated the app and added my OneDrive login to the online storage section.

Also is it normal for the backup to dropbox to go really really slowly even when connected to wifi?

Can anyone help?